NEW MSR is debuting the Thru-Link in its spring 2020 water treatment product line.

photo: MSR Thru-Link bottle/inline water filter

“Have Clean Water Instantly” with the MSR Thru-Link

“Just fill your reservoir by scooping it into a lake or river, and then drink,” said Sarah Courtney, Water Category Manager at MSR, of the Thru-Link. That’s how easy it is for hikers, trail runners, backpackers, and others to stay hydrated with the lightweight (2.5 ounces), in-line microfilter.

Originally designed for and tested for more than a decade by the United States military, the Thru-Link removes bacteria and protozoa and was engineered for fast, high-flow drinking by individuals on the move. It connects quickly to your existing hydration reservoir to be used as an in-line filter; while in camp, it can be set up as a gravity filter. 

For outdoor enthusiasts, Courtney says its biggest advantages are its efficacy and safety, speed (1.2 liters per minute), proven history, and universal fit with any reservoir.

“Proven by the U.S. Military for more than a decade, MSR‘s Thru-Link in-line microfilter combines the effectiveness, durability, and speed that minimalists and thru-hikers require in the backcountry," said Courtney.

Backcountry Use

“The Thru-Link is ideal for hikers, backpackers, and any other outdoor recreationalists who need safe drinking water on the move,” said Courtney. “And it is quite versatile on a range of trip profiles,” particularly in North America, where viruses are less common than during international travel. Chlorine tablets can be added to your reservoir before drinking to provide protection from viruses when abroad or otherwise needed.

The Thru-Link features a two-stage filtration chamber and meets the independent NSF Protocol P231 (the standard for microbiological water purifiers) for the removal of bacteria and protozoa. 

"With the MSR Thru-Link microfilter, there’s no need for hikers and backpackers to stop and filter their water. They just fill up their reservoir and go," said Courtney. “They have clean water instantly because the Thru-Link filters as they drink.”

First, its fast-flow hollow fiber removes water-borne pathogens (such as protozoa, bacteria, viruses, and multicellular parasites), particulates (such as dirt, sand, and sediment), and microplastics (increasingly found in water sources). Second, activated carbon reduces chemicals, tastes, and odors (including the taste of water reservoirs).

With a compact size of 1.6 by 7.5 inches and weight of 2.5 ounces, it won’t take up much pack space.

The Thru-Link is designed for above-freezing temperatures only. (Note: any water that lingers in the hollow fiber filtration can expand and cause the fibers to burst, compromising the integrity of the filter.)

Design Origins

While the Thru-Link became available to outdoor enthusiasts in 2020, it was originally developed for United States military use starting in 2006. Prior to its development, the U.S. military recognized the need for an individual, on-the-move water filtration system.

“You can imagine the U.S. military’s needs,” said Courtney. “They’re potentially in combat, so they don’t have time to stop and filter water with a pump or gravity filter. Prior to the Thru-Link, water collection and filtration was one of their most vulnerable times.”

A military survey of available commercial, off-the-shelf products found nothing that met their stringent requirements. MSR, which has its own in-house water lab for research, development, and testing, designed the single-pass, drink-through filter to address the technology gap. Since 2006 more than 360,000 Thru-Link microfilters have been used by U.S. servicemen and women. 

So, if it worked for the U.S. military, why did it take 14 years for the Thru-Link to be offered to the outdoor public? 

"At any given time, our in-house water research laboratory has a large number of filtration and purification technologies at its disposal, but the market’s acceptance of them changes over time" explained Courtney. “We had other water products in the pipeline that we believed would better meet the needs of outdoor users at the time,” like the award-winning Guardian Purifier.

The consumer and military models of the Thru-Link are essentially identical, sharing the same effectiveness, speed, and durability. The only change is an update in the ultrasonic-welded ABS housing to remove a material not compliant with California’s Proposition 65.

As for usage, the military uses chlorine tablets in conjunction with its filters, because they need virus protection internationally. Depending on where you travel, chlorine tablets are not necessary for many hikers and backpackers in North America. However, they can be dropped in your water reservoir after scooping water and before drinking through the filter for an extra level of protection, says Courtney.

Emergency Use

While MSR is an outdoor company, it's working to meet hydration needs not only in the backcountry and in the field, but also during emergencies and in low-resource communities around the world. 

The Thru-Link technology is also available in MSR's Emergency Home Water Filtration System, which comes in a hermetically sealed package for long-term storage and fits standard threaded home outdoor spigots and most utility sinks. While using different water treatment technology, the SE200 Community Chlorine Maker helps provide safe drinking water around the world through the company’s Global Health division.

“With large-scale natural disasters on the rise, it is apparent to us that there will be an increasing need for products in water treatment, an area where we have a very high level of technical expertise,” said Courtney. "At the end of the day, nearly all the products that we manufacture serve as survival tools.”

After all, whether you’re climbing your favorite mountains, serving in the military, or running long trails—easy access to safe, clean water remains essential.


Price MSRP: $39.95
Current Retail: $39.95
Weight 2.5 oz / 71 g
Dimensions 1.6 x 7.5 in / 4.2 x 19 cm
Flow Rate 1.5 L per minute
Capacity up to 1000L
Filter media Hollow Fiber
Filter pore size 0.2 microns
Effective Against Bacteria (99.9999%), protozoa (99.9%) and particulate (dirt, microplastics). Meets U.S. EPA drinking water standards and NSF protocol P231 testing standard for removal of bacteria and protozoa.


The MSR Thru-Link inline filter is a two-stage water filter design that MSR has been providing to the U.S. military for more than a decade; it will be available to the consumer market in spring 2020. The filter is unique in that it is configured to be used in-line with a reservoir/bladder that can be filled with unfiltered water on the go and then your water is filtered as you go along on your hike. In use, the Thru-Link Filter works well and has good flow, but depending on how you stow your bladder in your pack, the addition of the Thru-link filter can cause issues with your drinking tube and how it exits the internal cavity of your pack.

My initial impression is that the Thru-Link filter is a very good option for someone looking for a two-stage water filter that can integrate with their existing hydration system. I'll be continuing to use the Thru-Link Filter over the next couple of months and will provide a final review in the February/March timeframe.


  • Solid construction
  • Good flow rate
  • Quick disconnect is a nice feature when refilling bladder
  • Nice that MSR includes connectors for modifying existing bladders to accept filter
  • No special tools required for back flushing the filter
  • Good online instruction sheet


  • Need clearly stated instructions on the package to flush filter before first use
  • Addition of Thru-Link filter can create a potential issue causing pinching of drinking tube depending on how it exits the pack
  • You have to go on-line for instruction sheet—less likely someone will go look at sheet not included with a product


This review contains my initial impressions of the MSR Thru-Link water filter after getting out and using the filter on several trips hiking in the Western Washington Cascades. This will be followed up by a more in-depth review in the February/March 2020 timeframe where I can share my experiences using the Thru-Link filter over a longer period of time in different conditions and also explore the features of the design in more detail.

While the Thru-Link filter will be new to the commercial market in spring 2020, MSR has been supplying this filter design to the U.S. military for more than ten years. The Thru-Link is a two-stage design consisting of a hollow fiber membrane to remove pathogens and other small particulates combined with an activated carbon element that reduces chemicals, tastes, and odors. The physical packaging of the Thru-Link filter is unique in that it includes fittings at each end of the filter that allows it to be quickly installed or removed from a typical hydration bladder.

The integration of the Thru-Link filter to a water bladder supports a “scoop and go” approach where in use you would fill your bladder with an unfiltered water source and then your water would be filtered real time as you drink from the bladder through the Thru-Link filter installed in-line on the drinking tube of the bladder.

The Basics of What is Included

The MSR Thru-Link water filter comes packaged as shown in the picture below. 


The filter I received for testing was a pre-production item so this packaging was not the final version.

Included in the package I received are the items shown below and consisted of the Thru-Link filter with two male barb fittings. The filter I received was a pre-production version and MSR confirmed that all final production packaging will included both a male and female barb fitting which will enable the user to modify the drinking tube of just about any hydration bladder so that it will accept the quick disconnect fittings on the ends of the Thru-Link filter. The fittings that are included will work with any bladder that utilizes tubbing with a 1/4-inch inner diameter.


To use the Thru-Link filter you would either modify your existing bladder utilizing the two fittings included with the filter or if you have a compatible bladder like the Platypus 2L Big Zip EVO shown in the picture below, you would just undo the drinking tube at the quick disconnect and insert the Thru-Link filter like is shown in the picture below.


While assembling the Thru-Link filter to the Platypus Big Zip EVO is very simple and intuitive, there really is one step that you need to do with the Thru-Link filter before your first use that isn’t obvious and you wouldn’t know to do it unless you happened to have looked at the online documentation available on the MSR website. That initial step is to flush the filter to remove loose carbon particles left over during the manufacture of the filter. Now I wasn’t aware this was needed and didn’t do this before some of my initial testing, so I may have ingested a few bits of carbon which isn’t a concern at all (and I’m still kicking at this point…), but I think a step like that should be on the actual product packaging so there is a better chance the user would be aware of the need to flush the filter before its initial use.

Initial observations using the MSR Thru-Link filter

I have been using the MSR Thru-Link filter on a number of hiking trips here in western Washington and the filter has performed well. In the time I have been using the filter I have only run into one issue with how the filter impacts the integration/routing of the drinking tube with the primary pack I use.  

The integration issue I ran into with using the Platypus 2L Big Zip EVO/Thru-Link combination in my pack, which is a ULA Circuit, is that the drinking tube would sometimes kink when I used the exit feature on the ULA Circuit designed for the drinking tubes coming from bladders stowed in the hydration sleeve of the pack. This wasn’t an issue if I was using the Platypus 2L Big Zip EVO alone without the Thru-Link filter, but when I added in the Thru-Link filter it raises the exit point of the drinking tube from the bladder by 7.5 inches which results in a big bend to get the drinking tube back down to the exit feature on my pack which at times has resulted in kinking of the drinking tube.

I have tried to show the issue in the picture below, which is looking down into my ULA Circuit.


I have been able to work around this issue, and I could probably easily fix this issue by modifying the location of the female fitting on the Platypus Big Zip EVO, but for someone interested in the Thru-Link filter this is something that they may want to consider depending on the configuration of their pack and internal hydration sleeve. 

Cleaning the Filter

While I haven't run into a need to clean the filter just yet, the method described in the MSR instruction sheet is a simple backflush that doesn't require any special tools. The method simply involves sucking water through the filter until the tube is full between the filter and the bite valve. The next step is to disconnect the filter from the bladder and then blow back into the bite valve which pushes water back through the filter to flush out any debris or sediment. I have tried the process several times and have found it to be simple and easy and most importantly, something that I could easily get into the habit of doing when using this filter.

Flow Performance

With respect to flow, while there is a noticeable difference between having the filter installed and not installed on the Platypus 2L Big Zip EVO. With the MSR Thru-Link installed the flow rate is more than adequate and not much different than other bladders I own that don’t flow as well as the Platypus Big Zip EVO.


The list price of the MSR Thru-Link filter is $39.95, which I think is a very fair price for a two-stage filter and inline with the cost of similar filters currently available.

Summary and Initial Recommendation

Again, this is just my initial review of the MSR Thru-Link filter to share my experiences to date. I plan on continuing to use this filter over the next couple of months to gain more experience and also explore using the scoop and go approach that the use of the filter enables. For my final review I also plan on doing some testing to measure the actual flow rate of the Platypus 2L Big Zip EVO both with and without the Thru-Link filter and compare that to the 1.5 liter per minute flow rate stated in the MSR specifications for the Thru-Link filter. I may also try and measure the flow rate of other filters I own (BeFree and Sawyer Mini) to see how they compare.

Overall, my initial impression of the MSR Thru-Link filter is very positive at this point in my evaluation. In the meantime, if you have questions about the MSR Thru-Link water filter, please send them to and we'll do our best to address them in the final review.

Many thanks to both Trailspace and MSR for the opportunity to evaluate and test the MSR Thru-Link filter for the Trailspace Gear Review Corps!


I have had the MSR Thru-Link filter for two months and have used the filter on regular weekly hikes since receiving it for testing.

I have been using water filters on hiking and backpacking trips for over twenty years and have owned a variety of filters from an older MSR pump style filter to a Sawyer Mini and a BeFree, which has been my go-to filter for the last year or so. Most areas where I use water filters are in the Pacific NW and down in the Sierra where the water is generally of great quality and I only use a filter to protect for pathogens like giardia.

About: Mike Mineart is a retired mechanical engineer who enjoys hiking and backpacking in the Western Washington Cascades and down in California's Sierra where his recent focus has been doing section hikes along the John Muir Trail. Mike also enjoys fly fishing and is an active member of the Snohomish County (WA) Volunteer Search and Rescue and the Everett Mountain Rescue Unit.

Source: received for testing via the Trailspace Review Corps (Sample for testing and review provided by MSR)

Where to Buy

The MSR Thru-Link is expected in stores in spring 2020.

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